The need to process and transport a wide variety of solid particulates has grown more pronounced with the increased awareness of the environmental impacts of various industrial processes. Bottom ash, fly ash, spent bed ash, economizer ash, oil ash, petroleum coke ash, and other particulates form widely varying materials, each of which create different challenges for removal and processing. Over the years, different types or classes of systems have been used for removal and transport depending upon the application involved, not limited to hydraulic, mechanical and pneumatic-systems. For a variety of specific applications, pneumatic conveying systems are desirable over other approaches because they have a lower initial cost,—a lesser amount of maintenance, and are more environmentally acceptable.
Heavy or coarse material may present unique problems for processing in such systems. In—pneumatic conveying systems, conveyed solids are dropped into a pipeline to be transferred by a fluid prime mover (e.g., air, nitrogen or other fluids). The prime mover transfers momentum to the conveyed solids, which cause the conveyed solids to be picked up and transported down the pipeline with the prime mover for subsequent storage and/or processing.
If the conveyed solids in question are heavy and/or coarse materials, there is a tendency for such solids to drop to the bottom of the pipeline before the prime mover can transfer enough momentum for the solids to be picked up. A subsequent pile of stationary solids then progressively builds below the solids inlet point. This buildup eventually causes the cross sectional area of the pipe around the solids inlet to decrease, which in turn causes an increase in the velocity of the prime mover around the top of the pile. Eventually, the increase in velocity over the top of the pile sufficiently increases such that any additional solids dropped into the pipeline receive enough momentum transfer from the prime mover. Clearing the pile of solids in situ may take significant time, as only the top surface of the solids is exposed to the prime mover flow, which means that the surface area of solids exposed for momentum transfer is limited. While material may eventually be picked up and conveyed (depending upon operating conditions) the inefficient momentum transfer and partial plugging of the pipeline reduces conveying efficiency. Many operating environments have little or no opportunity to clear the pipeline for such potential chokepoints manually. Indeed, the operations involved may require continuous or near continuous operation at maximum conveying efficiency. Thus, there is a need for a system and method for efficiently entraining a solid particulate in a prime mover fluid so as to avoid a buildup of solids particulate in a pipeline.